<!DOCTYPE html>
<html lang="zh-CN">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .tooltip-boxs {
      margin-top: 10px;
      width: 180px;
      background: #666;
      border-radius: 8px;
      text-align: center;
      padding: 15px 1px;
    }

    .tooltip-boxs:after {
      content: "";
      width: 0;
      height: 0;
      border-style: solid;
      border-width: 10px;
      border-color: #666 transparent transparent transparent;
      position: fixed;
      margin-top: 15px;
      margin-left: -10px;
    }
  </style>
</head>

<body>
  <div class="tooltip-boxs">我是一个div</div>
</body>

</html>